It is necessary in hospital and other medical environments to sterilize medical instruments with steam or ethylene oxide. Various types of sterilization containers for such medical instruments have heretofore comprised muslin wraps, various paper wraps and sterilization containers. When using the various types of wraps, medical instruments are placed in a tray, wrapped by a recommended procedure, taped, labeled and placed in a steam or ethylene oxide sterilizer. The steam or ethylene oxide penetrates the wrap and kills the bacteria. Disadvantages in the use of the sterilization wraps include the repeated expenses of the disposable wraps, potential punctures of wrapping materials thereby causing contamination, limited shelf life of the wrapped instruments and the fact that the wraps are not stackable.
Various sterilization containers have been heretofore proposed which provide a hermetically sealed container with various filters which provide a relatively long shelf life, which cannot be easily punctured, which enable improved organization of the medical instruments and which are stackable. Sterilization containers made of metal such as stainless steel and aluminum have been used, but are relatively expensive. These devices are generally also opaque, thereby preventing a visual inventory of the container interiors. Consequently, sterilization containers made of plastics have been developed which can withstand the harsh environments of the sterilization chamber and which are clear such that inventories of the containers can be seen. Examples of such previously developed plastic sterilization containers are the Sterile-Case system manufactured and sold by Bemis Corporation and the Steri-Stor system manufactured and sold by Research Surgical Systems of Santa Ana, Calif.
Prior plastic sterilization containers have, however, suffered from the problem of condensate accumulation on the internal and external surfaces after sterilization. Although bacteria inside the container should be substantially eliminated through the sterilization process, medical technicians are trained to regard moisture as a breeding place for bacteria and thus condensate tends to cause technician acceptance problems, as well as providing an actual possible breeding ground for bacteria. In addition, the condensate increases the possibility for rusting and other deterioration of the metal instruments in the container.
Steam sterilization units, whether they be gravity steam, pulsating pressure steam or alternating vacuum and pressure or the like, all normally have a drying cycle. During the drying cycle, steam is applied to the jacket of the autoclave to create a hot environment and normally some vacuum is applied to the chamber in order to lower the boiling point of the moisture. The drying cycle is utilized to evaporate the moisture in the sterilization container wrap or the like. However, clear or translucent plastic sterilization containers have a relatively low thermal conductivity and thus do not allow the residual moisture to be evaporated within an economical time frame. The heat reaching the sterilization container within the sterilization unit comprises both conductive and radiated heat. The conductive heat tends to heat the container relatively slowly, in turn heating the moisture in the container and creating slow evaporation. The radiated heat emanates from the jacket of the autoclave, but such radiant heat is not able to be utilized in evaporation of clear or translucent plastic containers because the majority of the radiative heat passes through the clear surface of the plastic containers. The need has thus arisen for a plastic sterilization container which enables the sterilization of medical instruments and which also tends to prevent or eliminate condensate from being formed on the interior surfaces thereof within an economical time frame.